Spa Heaters & Elements Glossary

Posted by on 2/29/2024 to Glossary

Chemical Damage or Corrosion: Corrosion and other damage caused by improper chemical maintenance. Can include pitting, small holes, and the accumulation of deposits. This can result in non-working heater.
Clamp or Hose Clamp: Used to seal and secure vinyl tubing to heater or pump barb connections. Available in many sizes.
Copper Strap: Thin conductive copper leads. Attach to the circuit board creates a bridge between power supply and heater element. Has been replaced by insulated wires on most control systems. Carries live electricity.
Flow Switch: Safety device found on spas with low flow systems. Registers flow in the plumbing system. Closes the circuit to allow heater to engage.
Heater Assembly or Full Heater, Drop-In Heater: Refers to a full heater complete with elements and any included components.
Heater Connections or Electrodes, Element Posts: Electrical posts of the heating element. Connects power to the heater.
Heater Gasket or Tailpiece Gasket, Heater O-Ring: Round rubber gasket installed between heater flange and plumbing tailpiece. Can be flat or flat with raised rib.
Heater Tail Piece or Union Tail Piece: Male Buttress thread on one side for the heater union, and any variety of PVC or barb connection on the other side for plumbing. Available in many different sizes and connection types. Can be used for high-flow and select low-flow systems.
Heater Wires or Power Wires: Insulated copper stranded wires forming a bridge between power source at circuit board and the heater element connections. Carries live electricity.
Heating Element or Coil: Metallic component of a heater. Converts electrical energy into heat. Generally made of steel or titanium. Remains fully submerged in water during operation.
High Flow Heater: Type of electric heater used in hot tubs and spas that have either a dedicated full-sized single-speed, or dual-speed jet pump for circulation. Usually requires a minimum of 25 GPM to operate.
High Limit Cradle: Cover plate that holds the high limit sensor in place against the heater body. Protects sensor against ambient air temperatures.
High Limit Sensor: Safety device connected to control system. Senses resistance values which the circuit board interprets as temperature. Usually installed against the body of a heater. Designed to detect overheat conditions. Can shut down heater and/or system.
Low Flow Heater: Type of electric heater used in hot tubs and spas that use a dedicated low flow single speed circulation pump. Generally requires a minimum of 10 GPM to function.
Mounting Studs: Threaded posts with screws attached to heater body. Used to secure heater to a control box. Generally positioned to fit with a specific accompanying control system. Universal heaters include removable and repositionable mounting studs.
Pressure Switch or PSI Switch: Safety device found on spas with high or low flow systems. Registers flow in the plumbing system. 2 wire connections to the circuit board.
Pressure Tap: 1/8" NPT threaded hole in heater tube. Used for pressure swtich or sensor mount. Can be plugged if not in use.
Remote Heater: Heater that is installed away from the control system. Will generally include a power cord, and sensor wires if applicable.
Split Nut Heater Union or Heater Union Nut: Female threaded component of the heater union. Nut is split into 2 halves for installation. Each half is attached to each other by small screws. Can be purchased in 1.5" - 2.5" sizes.
Temperature Sensor or Temp Sensor, Thermistor: Safety device connected to the control system. Senses resistance values which circuit board interprets as temperature. Can be in direct contact with water or installed in a dry well.
Vinyl Tubing or Hose: Plumbing hose typically found in spas and hot tubs. Used for transporting water through the system. Clear, durable, flexible, and lightweight. Usually used for low-flow circulation pumps / heaters, ozones, jets, and air buttons.

Spa Heaters & Elements Glossary

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